'274 



DIANCHORA D1ANTHUS. 



times coarsely polished. It is also used in the form 

 of a powder by lapidaries, for cutting and engraving 

 upon harder gems ; by watchmakers in their jewelled 

 timekeepers ; and by glaziers for cutting glass. The 

 diamonds chosen for cutting glass are all crystallised. 

 The faces are curved, and hence the meeting of any 

 two of them presents a curvilinear edge. If the dia- 

 mond be so placed that the line of the intended cut is 

 a tangent to this edge near its extremity, and if the 

 two surfaces of the diamond laterally adjacent, be 

 equally inclined to the surface of the glass, then the 

 conditions necessary for effecting the cut are complied 

 with. In addition to the cutting and engraving of 

 glass, the diamond has been very advantageously em- 

 ployed in drawing minute lines on the surface of steel, 

 by which all the beautifully variegated tints of the 

 rainbow may be produced. 



The largest known diamond is probably that men- 

 tioned by Tavernier, originally in the possession of the 

 Great Mogul. Its size is about that of half an hen's 

 egg : it is cut in the rose form, and, when rough, is 

 said to have weighed nine hundred carats. Among 

 the crown jewels of Russia is a magnificent diamond, 

 weighing J95 carats. It is the size of a small pigeon's 

 egg, and was formerly the eye of a Brahminical idol, 

 whence it was purloined by a French soldier ; it passed 

 through several hands, and was ultimately purchased 

 by the empress Catherine for a sum equal to about 

 one hundred thousand pounds sterling. 



There is only one other diamond which our space 

 will permit us to notice. This is the celebrated " Pitt 

 diamond." It was brought from India by an English 

 gentleman of that name, who sold it to the regent 

 duke of Orleans, by whom it was placed among the 

 crown jewels of France. It weighs rather more than 

 136 carats, and was purchased for one hundred thou- 

 sand pounds. This country is not celebrated for the 

 size of the jewels which adorn the regalia of the sove- 

 reign ; but there are some beautiful models in the 

 British museum of those we have described. For an 

 account of the chemical constituents of the diamond, 

 see the First Division of this work. 



DIANCHORA (Sowerby). A fossil species of 

 shell, the animal of which is consequently unknown. 

 The shell is thin, adherent, regular, symmetrical, equi- 

 lateral, subauriculated, inequivalve, one valve hollow 

 within, and convex externally ; the other flat, articu- 

 lated by two very distant condyles. It belongs to the 

 order Palliobranchiata. 



DIANELLA (Ker.) A genus of tuberous rooted 

 herbs, indigenous to New Holland. Linnsean class 

 and order, Hexandria Monogynia, and natural order 

 AsphodelccE. Generic character : corolla rotate, regu- 

 lar, six-parted, and deciduous; stamens below the 

 germen, filaments bent, and thick at the top ; anthers 

 linear and erect ; style filiform ; stigma simple ; berry 

 globular, and many-seeded. These plants grow well 

 in sandy loam, and are increased by dividing the roots. 



DIANTHUS (Linnauis). A very numerous and 

 beautiful tribe of herbs, much esteemed for the ele- 

 gance of their flowers and for their fine scent. Lin- 

 naean class and order, Dccandria Digynia, and natural 

 order Caryophyllece. The pink, clove, carnation, and 

 sweet- William are all well-known favourites, and met 

 with in every flower-garden ; and some of the florist's 

 varieties are highly valued and sold at high prices. 



Carnations and pinks receive the greatest attention 

 and care from the florist ; the former is the Dianthus 

 Caryophyllus of botanists, and the improved variety 



of the clove of florists. It ranks as the chief of stage 

 flowers, as it combines elegance of form with variety 

 and delicacy of colours, and to these is added the 

 most delightful fragrance. To have flowers in the 

 greatest perfection, new plants must be raised every 

 year ; not but that old plants will continue to yield 

 flowers for several years ; but these being those of 

 branches, are never so large or so fine as such as are 

 produced on the central stem of a maiden plant. 

 Young plants are obtained by layering the lower 

 branches of the last year's layers ; and though these 

 be only the points of the secondary shoots, yet when 

 separated from the parent stock, they become, as inde- 

 pendent beings, ten times more vigorous and ampli- 

 fied than if they remained on their original roots. 



The cultivation of choice carnations forms a prin- 

 cipal part of the florist's business. They are usually 

 named, and the superior sorts, especially if they are 

 new, sell at high prices. New varieties are obtained 

 from seed ; but very fine stage or prize-flowers occur 

 but as one in a thousand interiors. A seedling of pro- 

 mising merit, may, by judicious culture, be advanced 

 to rank with the best : and it is by accident, and such 

 means, that our present stock of (hie carnations has 

 been in course of time obtained. 



The standard choice sorts are perpetuated by 

 annual layering. This is performed about the time 

 or soon after the plants are in flower ; but if layered 

 before, or as soon as the shoots are ready, the better. 

 If cultivated as stage flowers, they are kept in pots, 

 and of a pretty large size, in order that their branches 

 may be conveniently layered. If cultivated iu beds, 

 there they are also layered ; because there must be 

 an annual supply of young plants as well for beds as 

 for pots. 



Carnations are layered like other plants ; the lower 

 branches, which would not flower till the following 

 year (supposing them to be left on the parent stool), 

 are chosen ; an incision is made with a keen pen-knit'e 

 entered a little below the tjiird or fourth joint from 

 the top, and passed up the middle of the shoot as far 

 as the next joint. This separated piece is called the 

 tongue, and when the little piece below the bottom 

 joint is cut square off, it is ready to be fixed in the 

 soil. In layering, a little fresh compost is usually laid 

 round the plant to receive the layers. In this," little 

 furrows are made, and in which that part of the layer 

 between the tongue and the root is bent down and 

 firmly fixed by a little hooked stick. The layer is 

 then covered with about three-quarters of an inch of 

 the compost ; and at the same time the point of the 

 layer is gently raised upright, taking care that the 

 tongue be kept apart from the place whence it was 

 cut, and pressing the soil pretty closely over, and 

 around the point of the layer to keep it in place. 



New roots are soon produced at the lower end of 

 the tongue, and towards the end of September are fit 

 to be taken from the stools and planted in beds or pots 

 previously prepared for them. 



Some florists are very curious in forming their car- 

 nation compost j mixing together many different sub- 

 stances, as loam, sand, leaf-mould, and rotten dung of 

 various kinds. Such a compost may be very suitable, 

 but many successful cultivators use only the freshest 

 maiden loam, made sufficiently rich and porous by a 

 third part of thoroughly decomposed stable or old 

 hot-bed dung. In this, carnations, whether in pots or 

 in beds, thrive and flower in the highest perfection, 

 provided they receive all other necessary treatment. 



